Retrospective Analysis of Long-Term Adherence to and Persistence With DPP-4 Inhibitors in US Adults With Type 2 Diabetes Mellitus

Adv Ther. 2014 Dec;31(12):1287-305. doi: 10.1007/s12325-014-0171-3. Epub 2014 Dec 12.

Abstract

Introduction: Patients with type 2 diabetes mellitus (T2DM) must remain adherent and persistent on antidiabetic medications to optimize clinical benefits. This analysis compared adherence and persistence among adults initiating dipeptidyl peptidase-4 inhibitors (DPP-4is), sulfonylureas (SUs), and thiazolidinediones (TZDs) and between patients initiating saxagliptin or sitagliptin, two DPP-4is.

Methods: This retrospective cohort study utilized the US MarketScan(®) (Truven Health Analytics, Ann Arbor, MI, USA) Commercial and Medicare Supplemental health insurance claims databases. Adults aged ≥18 years with T2DM who initiated a DPP-4i, SU, or TZD from January 1, 2009 to January 31, 2012 were included. Patients must have been continuously enrolled for ≥1 year prior to and ≥1 year following initiation. Adherence was measured using proportion of days covered (PDC), with PDC ≥ 0.80 considered adherent. Persistence was measured as time to discontinuation, defined as last day with drug prior to a 60+ days gap in therapy. Multivariable logistic regression and Cox proportional hazards models compared the outcomes between cohorts, controlling for baseline differences.

Results: The sample included 238,372 patients (61,399 DPP-4i, 134,961 SU, 42,012 TZD). During 1-year follow-up, 47.3% of DPP-4i initiators, 41.2% of SU initiators, and 36.7% of TZD initiators were adherent. Adjusted odds of adherence were significantly greater among DPP-4i initiators than SU (adjusted odds ratio [AOR] = 1.678, P < 0.001) and TZD initiators (AOR = 1.605, P < 0.001). During 1-year follow-up, 55.0% of DPP-4i initiators, 47.8% of SU initiators, and 42.9% of TZD initiators did not discontinue therapy. Adjusted hazards of discontinuation were significantly greater for SU (adjusted hazard ratio [AHR] = 1.390, P < 0.001) and TZD initiators (AHR = 1.402, P < 0.001) compared with DPP-4i initiators. Saxagliptin initiators had significantly better adherence (AOR = 1.213, P < 0.001) compared with sitagliptin initiators, and sitagliptin initiators had significantly greater hazard of discontinuation (AHR = 1.159, P < 0.001). Results were similar over a 2-year follow-up.

Conclusions: US adults with T2DM who initiated DPP-4i therapy, particularly saxagliptin, had significantly better adherence and persistence compared with patients who initiated SUs or TZDs.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adamantane / analogs & derivatives*
  • Adamantane / therapeutic use
  • Adult
  • Aged
  • Cohort Studies
  • Diabetes Mellitus, Type 2* / drug therapy
  • Diabetes Mellitus, Type 2* / epidemiology
  • Dipeptides / therapeutic use*
  • Dipeptidyl-Peptidase IV Inhibitors / therapeutic use
  • Female
  • Humans
  • Hypoglycemic Agents / therapeutic use
  • Logistic Models
  • Long-Term Care / statistics & numerical data
  • Male
  • Medicare / statistics & numerical data
  • Medication Adherence / statistics & numerical data*
  • Middle Aged
  • Proportional Hazards Models
  • Retrospective Studies
  • Sitagliptin Phosphate / therapeutic use*
  • Sulfonylurea Compounds / therapeutic use*
  • United States / epidemiology

Substances

  • Dipeptides
  • Dipeptidyl-Peptidase IV Inhibitors
  • Hypoglycemic Agents
  • Sulfonylurea Compounds
  • saxagliptin
  • Adamantane
  • Sitagliptin Phosphate